Telegraph system



March 3, 1931. A.- F. CONNERY 1,794,756

TELEGRAPH SYSTEM Filed Jan. 18, 1928 .2 Sheets-Sheet 1 FIG.

ALDER F cofirjymv awvemtoz $51 a a;

March 3, 1931.

A. F. CONNERY TELEGRAPH SYSTEM Filed Jan. 18, 1928 2 Sheets SheQt 2 ALDER F. CONNERY avwwwcoz This invention relate E em and P r icu a ly-to,M g1iaPh y m$ in which transmission of; signals in one di rection 2 is efiected by reversing; thev'polarity ofthe line currentt and in -the other :direction Patented Mans, 1931,

ALDER r comma/0E ssmKrma w-mm, assrenoa T0 res ra n 'rn nqRKnf oABLE COMPANYgOF new Yong, LTQYJACORPORATION-0FCONNECTICUT o TELEGRAPH sYs'rnir s ja j iicatio fiiea .Tanuary 18, i928. se -m. 247,493.

making and breakingthe line circuit. ,It is often desired tosinstall ai telegraph Circuit between a central telegraph otfice and a small telegraph 'oflice' located ata point 50 to miles'distant. The vclosed-pircuit" Morse system ottelegraphy which only re quires a linerrelay,.jsounder and key art-each station -may be used for this purpose, but it' to is objectionableinfthat it is necessarytowlad j ust theline relay at each station. to com'pen f vsate for changes incline conditions due to leakage and other causes, operator at the central officeis usually experiencedgand.

has. no difliculty in k eeping the relay in a d j ustment, Y but the operator at the small Tof fice may be unable to keep the relay properlyg adjusted, and] this is particularly true. when complicated printing telegraph apparatus is: used becauseit is ;very: ldiificult todistinguish between the errors eaused improper line 'relay adjus tmentsjand those causedbyg ph pp ra i s i uble cu r nt onple system eliminates the need o-f adj ustmentsto compensate for yariation in line 'QOIldlf- Y tions, but the objection is that hothipositiye and 1 negative; polesv of line battery must be pr per j tme t o th a 'prin i e The use of available at b 0th terminals and furthermore 1t 1s necessary to operate. sw tches each; tlme awchang'e is madefrom sending to ,receiving conditions and vice-versa; A'further objec tion is that while onestation is sendi-ng it is,

not-possible for the other 1 station jto break? the ender i a 5 v v I v ,The principal object of, this invention is to provide a telegraph 'Isystem',l suitable. for the-accurate transmission of mes ages-over a :line conductor in either direction, which, requ1res no ad uStmentS to eompensate for Vanda plurality 'o f branchioflices, t v

In the drawingslike parts arerepresented change in linejconditions to be made at one] no adjustments are required.

Other; objects and advantages of t em:

In the accompanying drawings I igjl is a schematic diagram of anvenif we ,bodiment of th s nyentlon {as used] for communication between a-mam telegraph oflice andv a Single branch office.

FigII2 is, a .schematie diagram l a e r o an. 1 i bodlme'nt oi th1s1nvent1on as'used. for com-1' r. 0"' vention will beset forth n deta l 1n the following spe'cificatiom and particularly pointedoutin the appended claims; .ol.'

munic'ation' between a main telegraph oflic'e Referring to Fig. '1, the central telegraph: offioe is; shown in the part or thedra'wiiig' v marked ALandthe branch telegraph oiliceis shown at 13., The two oilices are cen ected; I

together line conductor L.

' The transmission from the central oiiice is effected by operating key l whieh' 'is kept:

short eircuited when .notinuse' by shortIcir-- c 1 cuiting; switch 2. "Key 1' I operates polef changer. relay, 3. Thefront and back conc tacts of, p'olechanger 3 are connected. to

grounded sourcesof current of substantially equal Voltage but of opposite polarity. The" changer splits at relay 4: so that partuof it goes through one winding of relay 4',' line L, polarized relay 5 at thebranch telegraph oifice and thence to groundwhile the remainder goes through the other Winding of tongue 15 of polechanger i3 is connectedto relayf and through variable resistance to I groundxfThe value of resistance 6 isfnon it is approximately one half the valuerof the .l jne cu rents The relay'responds to the many adjusted so the current flowing through polarity of the diiierence of the currents in I its two windings. The connections to therelays are such that, when neither station is sending, the tongue 7 of relay 4 has closed the circuit to sounder 8 and tongue 9 of relay 5 has closed the c1rcu1t to sounder 1d.

The retractile'spring 10, which is attached 7 to armature 9, tends to move the armature 9 away from contact 11. The pull of the re tractile spring 10 is small as compared to the force normally exerted on the armature by the line current. The purpose of this spring is explained in another part of this specification, Each signal sent from station A, reverses the polarity of the line current which energizes relays i and 5 which respond and operate the sounders connected to them. In the case of station A transmits ting, the object of operating sounder 8 is to produce a home record or" the sent signals.

7 The signals are read fromsounder 14 at station Inthis' case it is apparent that a reasonable amount of leakage will have no disturbing effect on'the operation of relays 4t or 5 -since theyare, in this case, responsive to the polari ty oi thesignal rather than the cure rent strength. 1 V

Station B transmits by manipulating key V 12 which is short-circuited, when not in use,

by switch '13. Operation of key 12 opens and closes the line circuit. Relay 5 responds to this opening and closing of the line 'circuit because, during the period that the line is open, the spring 10 pullsthe armature 9 away from contact 11. In this manner the home record of sending at station B is produced. The manipulation of key 12 also operates relay iat station A because when the.

current in the line coil is interruptedor reduced the current inthe other winding, the value of which is regulated by resistance 6, controls the relay and thereby operates sounder 8. i j

Fig. 2 shows how this invention may be used. in connection witha main telegraph office and a plurality of branch telegraph ofiices-J lathe drawing only two branch oifices are shown but it should be understood that this number may be increased when dea distantstation.

sired. The two branch otlices are shown in the parts of the drawing marked B and Of The B station is identical with the, B station shown on Fig. 1. The C station is simiis of insutficient strength to overcome, line' induct-ion when the line circuit is opened at It will be pparent'irom the fo g scription that a telegraph system embodying this invention is suitable for use between a maintelegraph ofiice and oneor more branch offices and that only one adjustment is, required to compensate for a change in "line conditions and this adjustment is made at the main office.

Although the invention hasbeen disclosed V and described in conjunction with the Morse system of telegraphy it should be obvious that it is suitable for use in connection with a printing telegraph system andit may also be used in connection with other means of transmitting intelligence without departing from-the spirit and scope of the presentin vention. i

- I claim; 7 V

1. In a telegraph system, a main station, a

branch station, aline circuit connecting said stations, polechanger transmitting means at said 'main station, polarized receiving means atsaid branch station responsive to'signals transmittedfrom either of said stations,'make and break transmitting means at said branchstation, double-wound polarized receiving means at said mam station responsive to sig nals transmitted from either of said stations,

one of said windings being connected inse'ries with'said line circuit and the other winding being in series with a variable resistance, said variable resistancebeing for the purpose of adjusting the receiving means at said main station to respond to signals transmitted from said branch station, despite variation in electrical conditions ofsaid line circuit.

' 2. In a telegraphsystem, a main station, a

1 branch station, aline connectionbetween said stations, polechangertransmitting means at said main station, polarized receiving means at said branch station responsive to signals transmitting from either of'said stations, make and break transmitting means at said branch'station, double wound polarized rei ceiving means at said main station responsive to s1gnals transmitted from either of saldstations,;said windings b'eing'connectedin op position'to each'other, the first of said windings being connected in series'with said line circuit and t-hesec0ndof said windings being connected to ground, means for'varying the relative magnetic strength of the said windings, the direction of current through each'of said windings being controlled by the transmitting meansat the said main station.

' 3.111 a'telegraph system, a'mainstation, one or more branch stations, a series connected line circuit between'said-stations, polechanger transmitting means at-said main station, polarized receiving meansat each of said branch stations'responsive to signals transmitted from the home station as Wellas from the said main station, make and break transmitting means at said branch stations, double wound polarized receiving means at said main station "responsive to signals trans 'ti'on, polarized receiving means at each of said branch stations responsive to signals transmitted from the home station as well as from the said main station, make and break transmitting means atsaid branch station,

double-wound polarized receiving means at said main station responsive tos gnals transmitted from any of said stations, said wind- 4 ingsbeing connected in opposition to each other, the first of said windings being con: nected' in series with saidline circuit and the" second of said windingsbeing connected to ground, means for varying the relative magnetic strengthof the said windings, the di rection of current through each of saidwindings being controlled by the transmitting means at said mainstation. V a 5. In a telegraph system, amain stationand one or more branch stations in a series circuit, a single source of current at the main station supplying the entire line current, transmitting means at'the main 7 station adapted to reverse the polarity of current supplied from said source, transmitting means at a branch circuit adapted to open and close the line circuit, and relay means at each station responsive to. both transmitting means. a V I 6. A telegraph system comprising a main station having a polar differential receiving relay, an outgoing line circuit one side of which is connected to one arm of said relay, a resistance greater than said line resistance connected between the other arm of said relay and the other side of said-line circuit, acurrent source at the main station for'supplying ing means responsive to signals transmitted from the home station as well as from the said main station, make and break transmitting means at said-branch" station, doublewound polarized-receiving means'at said main station responsive to signals trans niitted from any of said stations, said windings being connected in opposition to each other, the first of said wmdings belng connected-in series with said line'circuit and the second of said windings being connected to ground, means for varying the relative mag- 5 netic strength of the said windings, the di-,

rection of current through each of said Windings being controlled by the transmitting means at said main station. f

i ALDER-v F. CQNNERYL} I all-the line currentfor the entire line, a transmitting device comprising means for connecting said source between the mid tap of i said relayand the other side of said line circuit and for reversing the polarity thereof to transmit signals, and one or more branch 7 4 means at said main station, polarizedreceiv- 

